1. Field of the Invention
The invention relates to an arrangement for simulating the force effects on the wheel of a motor vehicle resulting from operation of the motor vehicle, wherein the arrangement makes it possible to introduce different force effects from the three force directions into a ground contact point of the wheel and to thus simulate the force effects of the street in a driving test.
2. Description of the Related Art
The arrangements which are known in this context are basically complex special constructions with a cost-intensive individual manufacture (usually in-house knowledge not available in published form).
It is an object of the present invention to provide an arrangement of the aforementioned kind which ensures the same function but is comprised of simple components.
In accordance with the present invention, this is achieved in that a frame-shaped wheel adaptor is provided which is arranged in a vertical plane and which is articulated with a first push rod, extending in a horizontal plane intercepting the wheel center and simulating a longitudinal force, wherein the wheel adaptor has in the area of the fictitious ground contact point of the wheel a U-shaped cutout which is penetrated by a vertical bolt which extends with its longitudinal axis in the vertical plane and intercepts the ground contact point of the wheel and the wheel center and is connected by a first joint with a multi-part housing, which housing is rigidly connected to a second push rod, extending transversely to the vertical plane and with its horizontal longitudinal axis through the ground contact point of the wheel and simulating a lateral force, and is coupled via a second joint with a third push rod, that is rotated by 90xc2x0 relative to the second push rod, extends with its longitudinal axis in the vertical plane and through the ground contact point of the wheel, and simulates a longitudinal force, wherein the center points of the first and second joints coincide with the ground contact point of the wheel, and wherein the wheel adaptor is articulated on a substantially vertical rod-shaped force introduction member below the cutout whose longitudinal axis extends coaxially to the longitudinal axis of the vertical bolt.
The gist of the invention is the play-free universal joint-type support of the ground contact point of the wheel by means of two joints nestled into one another and having different radii. The directions of the simulated longitudinal force, of the lateral force, and of the vertical force extend through these two joints. All three force directions are positioned substantially perpendicularly relative to one another, but still allow to vary the angles relative to one another within limits. The components which are used for the arrangement according to the invention result in a small configuration size within short manufacturing times, wherein, however, a simple size variation is possible. The simple components allow moreover a simplified maintenance. Accordingly, the entire construction and manufacturing expenditure in comparison to the prior art can be considerably lowered.
By means of the second and third push rods, lateral forces and longitudinal forces can be simulated. The force introduction member simulates the vertical force resulting from the wheel contact on the road surface. Moreover, via the first push rod a further longitudinal force can be simulated. The application of the longitudinal forces via the first and the third push rods makes it possible in a simplified manner to simulate braking torque. The push rods and the force introduction member are subjected to the effect of preferably hydraulically operated cylinders, wherein, in principle, frequencies as desired can be applied. Under certain experimental conditions pneumatically loaded cylinders are also conceivable.
The housing is basically of a fork-shaped configuration with an upper and a lower leg wherein the end faces of the legs are spaced apart and position-secured by a holding plate at the end faces.
According to a further embodiment, it is advantageous when the first joint is comprised of a sleeve secured circumferentially on the vertical bolt and having a spherical section as an outer surface. Moreover, the first joint is comprised of a joint bushing secured in the housing and having an inner surface which is matched to the outer surface of the sleeve. The housing above and below the joint bushing has conically widening inner cutouts. The conically widening inner cutouts are formed within two pressure members which are detachably secured from above and below in corresponding receptacles of the legs.
The conical cutouts of the housing are sized such that all conceivable movements of the housing relative to the vertical bolt can be accommodated. The sleeve preferably rests against a step of the vertical bolt. Its position is secured by a spacer sleeve which extends between the sleeve and the lower horizontal boundary of the U-shaped cutout in the wheel adaptor. Sleeve and spacer sleeve are position-secured via the step on the vertical bolt by means of a setting screw screwed from below into the vertical bolt and supported on the wheel adaptor.
The second joint is advantageously comprised of a sleeve, which is position-secured in the housing so as to surround the first joint and which is provided with an outer surface formed as a spherical section as well as with an inner cylindrical surface, and of an annular swivel head of the third push rod which has an inner surface that is matched to the outer surface of the sleeve.
The sleeve of the second joint is position-secured by means of the pressure members. For this purpose, the pressure members have corresponding cylindrical receptacles for the sleeve.
In order to ensure a proper play-free mounting of the two joints, according to another embodiment a compensation bushing is integrated between the joint bushing of the first joint and the cylindrical inner surface of the sleeve of the second joint. Joint bushing and compensation bushing are supported, on the one hand, directly on the upper pressure member and, by means of a pressure disc, preferably of plastic material, on the lower pressure member.
Mounting of the wheel adaptor as well as of the joints and also maintenance are facilitated and simplified when, according to a further embodiment, the wheel adaptor is of a two-part construction and the vertical bolt is detachably integrated between the two parts. In this connection, the vertical bolt, which is optionally of a multi-part construction, engages with its cylindrical longitudinal section a corresponding cutout of the lower part of the wheel adaptor. At the upper end the vertical bolt has a flange-shaped console which is screwed onto the upper horizontal boundary of the U-shaped cutout which is a component of the upper part of the wheel adaptor. The vertical bolt is securely axially centered between the two parts of the wheel adaptor by means of a central pin, which begins at the console and engages in the upward direction a cutout of the upper part.
Also, the force introduction member which extends substantially vertically and is rod-shaped is coupled with the wheel adaptor by a joint. For this purpose, the wheel adaptor has two downwardly oriented brackets. The brackets are penetrated in the horizontal direction by a support bolt. The support bolt supports a bolt sleeve with an outer surface having a spherical section contour. It is engaged from the exterior by a surface-matched ring-shaped swivel head which is connected to the force introduction member. The sleeve is position-secured in the axial direction of the support bolt relative to the two brackets by spacer bushings.
In order for the wheel adaptor to be secured in its position for force introduction from the three force directions, according to a further embodiment a slanted strut is positioned between the lower end portion of the force introduction member and a connecting flange, provided for connecting the force introduction member to the wheel adaptor and displaced laterally relative to the vertical plane. This slanted strut is detached, i.e., made inoperative, when braking torque is to be simulated by means of the first push rod as well as the third push rod.